Truing device for the wheels of grinding machines



Aug. 16, 1932. s. EINSTEIN ET AL 1,371,504

TRUING DEVICE FOR THE'WHEELS 0F GRINDING MACHINES Filed Jan. 28, 1924 3 Sheets-Sheet 2 i 1 I i I u i l;

7217077: eg/s 932. s. EINSTEIN ET AL 4 TRUING DEVICE FOR THE WHEELS OF GRINDING MACHINES Filed Jan. 28, 1924 s Sheets-Sheet 5 Patented Aug. 16, 1932 UNITED. STATES PATEN O F SOL EINSTEIN AND LESTER. F. NENNINGER, OF CINCINNATI, OHIO, ASSIGNORS, BY

MESNE ASSIGNMENTS, TO THE CINCINNATI :NATI, OHIO,'A CORPORATION OF OHIO GBINDERS INCORPORATED, 01? CIN- rnume mivIcE FOR THE want-ins or enmnme mcnmns Application filed January 28, 1924. Serial No. 689,068.

, 1 1111s lnvention pertalns to mechanism or apparatus for-truing the grinding and governing or control-wheels of centerless grinding machines of the type in which said wheels are peripherally opposed one to the other, and 1ts purpose is to provide means, preferably, though not necessarily, constituting a permanent part of such machines, capable of truing each of such wheels under the varying adjustments and conditions of use peculiar thereto. As the wheels have to be trued quite frequently if the machine is run to or nearly to capacity, it is quite desirable that the truing devices be kept on the machine and in position' for use without the necessityof removing other parts or fittings, or destroying adjustments. A prominent feature of'the invention is the attainment of --a construction fulfilling these conditions, yet permitting ready removal if necessary. z

The invention will be described and 'explained in connection with the accompanying drawings, in which: 3 a

'Figure 1 is a side elevation of a grinding machine of the type stated, equipped with the novel truing devices a Fig. 2 is a perspective-view, showing on a larger scale the truing device as used in connection with the grinding wheel;

3, a top plan view of the .truing'device as mounted to true the wheel; Fig. 4, a'vertical section on the line i-of Fig. 3, looking in the direction of the arrows thereon; v

Fig. 5, a partially sectional elevation of the governing or control-wheel carrier, and the governing or controlmechanism for advancing and receding-the same;

Fig.6, a'detail View of a part of the mechanism shown in Fig. 6;

Fig. 7 a cross section on the line 77 of Figs. 1 and 4;

. Fig. 8, a similar section on the line 8-8 of Fig. 4,.but on a larger scale than 7;

Fig. 9 an enlarged perspective viewof theadjustable diamond-carrier of the truing mechanism of the governing or control-wheel. In order to make clear the invention and its use, the grinding machine and its mode of adjust'ment and operation will first be outlined briefly, in connection with Figure 1.

As shown, the grinding machine comprises a substantial base or main frame 1, a grinding wheel 2 and a governing or control-Wheel 3, said wheels being of the same or similar material and texture, and each mounted upon a spindle or arbor carried'in bearings or in a single sleeve bearing. The bearing or bearings of the arbor of Wheel 2 is or are advisably fixed rigidly in position, as it is important to prevent or reduce to a minimum any vibration of the machine or its parts, more likely to be produced by the large and swiftly rotating grinding wheel than by any other part of the machine. The spindle or arbor of the governing or control-wheel 3 is carried in a sleeve bearing supported by a yoke or bracket 4, secured'to'and supported by a shell'orcarrier 5 slidableupon waysand adapted to be -moved thereonjtorcausethe periphery of wheel 3 tokapproach" more or less nearly to that of wheel 2, and thereby to gage and de-' termine the grinding space between them. Carrier 5 is guided by ways, preferably formed upon the upper face of a slide 6,,in

:turn movable upon like guideways formed on'the bed or topplate of the grinding machine.

Both the carrier 5 and the slide 6 are pro vided with conventionallyindicated means as camming levers 5afor'clamping them to the 4 ways 6a and 6?) on which thevrespectively move, and by so clamping both they will be held against any movement; on releasing the slide 6, it and the carrier clamped to it may be'moved as one; and on releasing both the carrier and the slide, either may be moved relatively to the other. In this way a workrest 7-8 carried by the forward or inner end of the slide 6, may be correctly positioned between and relatively to the grinding and the governing wheels, and the slide be thenclamped to maintain such adjustment; the

carrier 5 may next be moved to bring governing-wheel 3 into proper relation to the work-rest and grinding, wheel, and then be clamped to the slide 6, thus securing the carrler and governing wheel at their proper adjustment; or the carrier may be freed for movement back and forth, as required.

In the use of the machine two modes of operation are interchangeably employed, according to conditions, such as the amount of grinding desired, the character of the material to be ground, the presence or absence of head, shoulder, or enlargement at any point in the length of the work ground, etc.

If plain cylinders of uniform diameter, considerable length, and requiring relatively little grinding, are to be handled or produced, it is often expedient to tilt slightly the axis of the governing or control-wheel 3 relatively to the axes of the grinding wheel 2 and the work, and to the work-supporting face of the work-rest bar or blade 8, and thus to cause an automatic rotation and axial feed or advance of the work over its supporting rest. Such feed is due to the slower rotation and greater grip or hold of the governing wheel 3 as compared with that of the grinding wheel, and to the fact that the thrust of wheel 3 is not perpendicular, but at an ob tuse angle to, the axis of the work, and is hence divided between rotating and axially advancing the same along the work-rest.

If plain cylindrical grinding of only one diameter, or conical grinding, is to be per formed, but the length of the portion to be ground is not in excess of the width of the working face of the grinding wheel, the grinding may be effected more rapidly and uniformly without axial feed. In such case the axes of the wheels and work, and the work-supporting face of the work-rest blade or bar will be placed and maintained in common radial plane, and the two wheels gradually approached-until the requisite depth or amount of metal is cut away, whereupon the wheel carried in a movable support or carrier will be retracted to free the work and afford ample space to receive another ungroun'd blank or object after which the stated cycle of operations will be repeated so long as blanks of the same form and dimensions are to be ground.

If headed or shouldered objects are to be ground, similar adjustments will be made, the wheels being dressed and a work-rest blade or bar provided to suit such object, that is, shouldered if the object to be ground is shouldered, beveled if the work to be ground is conical, and, so on. 7

When the governing or control-wheel has its axis inclined to cause it to feed or advance the work, its circumferential face is dressed, or soon wears away, to a slightly hollowed or concave form between its ends, affording a line bearing or contactwith the work across the entire width of the peripheral face of the governing or control-wheel, and thus ensurand certain rotation and feed of ing uniform The curvature under ordinary the work.

working inclination of the axis of the governing wheel is scarcely perceptible to the eye, even when a straight-edge is laid overthe wheel parallel with its axis; but it should be present, and will be automatically produced in a short time, through the wearing effect of the work against which it presses, ifnot dressed to such form.

Work is sometimes ground with its axis in horizontal plane with the axis of the grinding wheel, sometimes higher, and sometimes lower, work-rests of varying height being provided, or adjustment of the rest being made to suit particular conditions in this respect.

It will be apparent from what has been said that truing of the wheels must be made with due regard to all the various conditions stated, and the present invention makes provision for so doing.

Referring now more particularly to Figs. 2, 3 and l, the construction of the truing mechanisms per se will be explained.

As seen in Fig. 1 these mechanisms, which in the main are quite similar, are located upon the tops of the wheel guards or hoods where they in no way interfere with any other parts or devices, or with the introduction and removal of work handled, and they are designed to remain in this position ordinarily, though of course removable for repair or replacement of parts. Parts of like construction in the two truing devices will be indicated by like numerals, and-described in connection with the figures illustrating the two structures.

Figure 2 shows the truing device for the grinding wheel, carried by the wheel-guard 9 and hinged to lugs 10 formed thereon, and permitting the tilting of the entire structure from its normal position in which its base-plate 11 is truly horizontal and parallel with the axis and with the circumferential face of the grinding wheel 2, when the wheels 2 and 3 are ofcylindrical form in whole or in part, arranged as indicated in Fig. 1, and the grinding machine stands upon a level base. The base-plate 11 isprovided with a dovetail guide rib 12 on its upper face, upon which is fitted and arranged to slide, a tubular upright post 13, the upper end of which is radially slitted, and is formed with lugs or ears 14 on opposite sides of the slit, which may be drawn together by a bolt or screw passing through them to slightly contract post 13 and cause it to clamp or bind a cylindrical tubular sleeve 16 ,fitting snugly within the opening in said post. The lower portion of post 13 is formed with a dovetail guideway to fit the guide rib 12, said rib and guideway being parallel to the axis of the grinding wheel. For the purpose of moving the post 13 and-parts carried thereby, longitudinally of the rib 12, there is provided a screw 17, swiveled in an arm or bracket 18, and entering a hole or seat in the base of post 13 to one side of the rib 12 and the guideway in the base of said post. A hand-wheel 19 serves for rotating the screw in either direction, to move the post to any desired position on its guiding rib -12.

As shown in Figs. 2 and 4 the tubular sleeve 16 is provided in its outer surface with a longitudinal groove 20'to receive the reduced end of a screw 21 passing through the wall of the post 13, to'prevent rotation of the sleeve 16 while allowing free longitudinal movementthereof. By loosening the bolt or screw 15 the tubular sleeve 16 is freed, and may then be moved vertically by hand or otherwise.

Within and closely fitting the bore of sleeve 16 is a stem 22, shown in dotted lines in Fig. 2. in cross section in Fig. 8, in Fig. 9, and, partly in sectionin Fig. 4. This stem carries at its lower end the diamond 23 by which the circumference of the wheel is dressed, the diamond being mounted either directly in the lower end of the stem 22 or in a-separate carrier 52, one form of which is shown in Figs. 4 and 9, and will be described later. Rotation of stem 22 is precluded by a key or feather 24 projecting into grooves formed respectively in'the interior of sleeve 16 and exterior of stem 22, as seen in Fig. 7. To adjust the stem 22 up or down there is provided a screw 25, Figs. 4 and'7, having a collar or shoulder 26, and swiveled in a circumferentially threaded plug or nut 27,

above which there is secured to the stem a knob or head 28, preferably furnished with radial arms to enable it to be rotated readily despite the quite close fit and friction betweenthestem 22 and its guiding sleeve 16. The threaded portion of screw 25-enters a tapped hole in the upper. end of and concentric with stem 22, and consequently serves when, the knob and screw! are rotated, to raise or lower stem '22. To enable the attendant toadjust the stem 22 with nicety and exactness, a scale 29 is marked on the circumference of the knob or head 28, or upon the upper end of sleeve 16, and a zero mark made upon the other of said two members, so that the advance of the diamond 23 toward the wheel may be read in thousandths of an inch or other small divisions.

The stem 22 should movesubject to a reasonable degree of friction, and should be firmly held against vibration. To this end it is not only closely fitted within-the sleeve 16, but friction blocks 30 with follower screws 31 are provided at different points in the.

length of said stem, to take up any play that might otherwise exist. These friction blocks and screws are shown in Figs. 4, 7 and 8.

As seen in Fig. 2, the base-plate 11 of'i the grinding wheel truing mechanism has a projecting lug 32, perforated to receive the shank or body of a screw or' bolt 33,. the threaded lower end of which screws into a threaded hole in the top of the wheel-"gu'ard 9, or in a raised projection 34 thereomthus' serving to hold the plate againstrising-and against horizontal movement or play. hen

it is desired to dress the peripheral surface screw 35 having a milled head, said screw being'reduced in diameter at its lower extremity to enter a socket in the raised projection 34, and provided with a washer 36 at the top of the reduced portion to afford a broad bearing on the raised projection. The threaded body of screw 35 intermediate the milled head and the washer 36 is screwed into or passes through a correspondingly threaded hole in the lug 32, and as the screw 35 and its bearing collar are held down upon the bearing face of the raised projection 34 by the weight of the truing device, rotation of said screw in the proper direction will cause elevation or tipping. of the base-plate 11 and parts carried thereby.

The portion of the screw 35 below the milled head is made of rather-large diameter, to permit a: scale to be marked thereon in sufliciently fine graduations, which immediately w are read from or in relation'to a fixed pointer 37 secured to thelug 32 and reaching tothe enlarged portion'of the screw 35, as shown in Fig. 2.

If now it be desired to dress the surface of wheel 2 to cylindrical form, it is merely necessary to tighten the binding screw 33 thus holding base-plate 11- firmly in horizontal position; turn the head or knob 28 to lower the diamond 23 to the proper depth to cut into the circumferential'face of the wheel 2; set the wheel into rotation; and turn the hand-Wheel 19 slowly to causethe diamond to feed transversely across the circumferential faceat such a speed as shall ensure its encountering every portion of the face of said wheel during the rapid rotation thereof. It may be thus passed over the face several times, if this be necessary to completely and accurately true the same.

If it be desired to bevel the circumferential face of. wheel 2 across its entire width, or

over a portion of its width, the screw 33 will i be loosened, and screw 35 turned to tilt the dressed to a bevel or inclination to the remaining portion, the diamond being gradually fed forward until the full width of bevel is cut away or trued to the proper angle.

The construction, and the mode of adjustment and of operation of the truing device for the governing or control-wheel 3 is in the main essentially the same as in the case of the grinding wheel, but special adjustments must be made to compensate for the tilting of the governing wheel axis out of .parallel with the axis of the grinding wheel,

if such tilting be done, and also to compensate for changes in elevation or lowering of the work axis above or below the common plane of the grinding and the governing or control-wheel axes. As stated, parts common to the two truing devices bear like numerals. Parts which diifer will be given other numerals.

Referring now particularly to Figs. 3 and 4, the second truing device, or that which trues the governing or control-wheel, will be described as to those features which are different from or additional to those of the grinding 'wheel truing device. As to the upright post 13, sleeve 16, stem 22, adjusting screw 25, and diamond 23, the two structures are substantially or actually identical. The base plate 38 of the governing-wheel truing device, however, is formed with a circular neck or collar 39 on its lower face and at its midlength, to fit a seat 40 formed in the top or hoodportion of yoke 4, thus permitting the base-plate 38 to be swung about the axis of stem 22 to an extent allowed by slots 41 formed in said base-plate, and bolts or screws 42 passing through said slots, the slots 41 being curved concentrically with the circular neck 39. The top of base-plate 38 is.

recessed to permit the tops of the bolt heads to lie flush with or slightly below the end portions 43 of said plate, so that the tubular post 13 may pass freely back and forth over the full length of the base-plate, under controlof a screw. 44 and hand-wheel 45, the screw being swiveled in a bracket 46 rising from the base-plate 38.

One end of the base-plate 38 has a portion .cut away or curved and mad-e concentric with the axis of stem 22 and neck 39, as shown at the-,lower right-hand corner of said plate in Fig. 3. and this surface is provided with graduations 47 to be read in connection with a pointer or indicator 48 located upon the hood or topportion of yoke 4. The graduations 47 correspond to graduations49 on the curved edge of the portion of carrier 5 abutting against theyoke 4, as indicated in Figs. 1 and 3, and the base-plate 38 will be swung in the proper direction a number of degrees or spaces corresponding to the number to which the yoke 4-is thrown from its normal or zero position, as shown by the scale 49. In this way compensation may be made for the tilted relation of the governing wheel axis relatively to the common plane in which the axis of the grinding wheel and the axis of the Work on the work-rest lie, and in which the axis of the control wheel also lies when inhorizontal plane.

As the work to be ground is positioned with its axis in, above, or below the common plane of the grinding and the governing wheels, according to the nature of the body ground and other conditions, compensation must be made in the setting of the diamond for such variations in the position of the wheels. This is attained by making and equipping the lower end of stem 22 of the governing-wheel truing devices as indicated in Figs. 4 and 9. As best shown in the latter figure, the lower extremity of said stem is of squared or rectangular form, and has a dovetailgroove or seat cut 111 its lower face, and extending in-a fore and aft di- 'Nicely fitting the dovetail seat in the extremity of stem 22 is a longitudinally-movable slide 52, graduated on its side face as shown in Figs. 4 and 9, so that the exact extent of its movement, which will be manually effected, may be read upon the scale in connection with the front or rear wall of the squared extension of the stem 22. The graduations may be such as desired, as hundredths of an inch, or like small divisions of whatever scale is used for the other adjustments of the machine. The diamond 23 is in thisinstance. set in and projects from the bottom face of slide 52, and hence will be carried from its normally central or axial position relative to stem 22 to a position in advance or in rear thereof, if said slide 52 ,be moved forward or backward from its normal position, in which, as indicated, the point of the diamond is concentric with the axis of stem 22.

In F1 f=. 4 a suitable mounting of the governing or control-wheel 3 is illustrated, and

may be briefly explained with a view to a better understanding of what has been said of the tilting or tipping of the axis of said wheel. The vertical section indicated in this figure is taken in the vertical mid-plane of the grinding and thegoverning' wheels when both have their axes horizontalandconsequently parallel with each other; orv in other words,'it is taken in a vertical plane lying midway betweenv the radial or side faces of said wheels, "except as to the pivot-pin or stem 53 and clamping bolt 54 shown in said figure. Of these the pivot-pin or stem 53 is partially broken away and shown in section, while the bolt 54 is shown complete and'not in section.

outer or end wall of the yoke member 4 which carries the governing wheel, its arbor, and bearing sleeve, and through a neck or horizontal extension of the inner end wall of the carrier or shell 5. The end of pin 53 nearest the governing wheel is headed, and its opposite end is centrally drilled and tapped to receive the reduced and threaded end of a stem 55., which after passing through a capplate 56 and washer 57 screws into the threaded socket of pivot-pin or stem 53, and serves to draw the head of stem 53 firmly against the yoke 4, and to press and hold the outer or rear face of said yoke into close and firm,

contact with the inner or forward face of shell or carrier 5. The outer and larger body of stem 55 is carried through an opening in the outer or rear wall of shell or carrier 5,

I and is there made polygonal, to receive a wrench or other implement by which to turn it in order to tighten or loosen the pivot pin 53, as desired.

Further to hold the yoke 4 in close contact with the carrier 5, and to preclude tilting of the yoke after it has been accuratelyadjusted, the bolt 54 is provided. This passes through an arcuate slot 58 in the back-plate orwall of yoke 4, and screws into a hole tapped and threaded. in the forward face or wall of the carrier 5. When it is desired to tiltthe shaft 1 clamped at such adjustment by the tightening of-the bolt 54 and the stem 55.

Eigures 5 and 6 illustrate means for advancing and receding the carrier 5, yoke 4 and governing wheel 3 carried by said yoke,

with and without the slide 6. This mechanism is used both for initially adjusting the work-rest and the governing or control-wheel relatively to the grinding wheel, and for advancing the governing-wheel progressively when the grinding is done without automatlc axial or spiral feed of the work. Said mechanism comprises an internally threaded sleeve 59 swiveled in a boss 60 of the outer wall of shell or carrier ,5, and provided with a worm-wheel 61 with which meshes a worm or screw 62 journaled in a swinging support and held in an elevated with worm-wheel 61. The pivot-pin or stem 53 passes through the r A hand le er 68 .is attached to the sleeve 59, o'rito the worm-wheel formed therewith, bywhich'said sleeve may be given a partialrotation under the control .of the operator or attendant, and subject to constant determi nation, through the sense of feeling, of the pressure at any time exerted by the govern ing-wheel against the work. This hand-level 68 thus afiords convenient'and dependable means for moving the carrier 5, and consequently the governing wheel 3,gradu al ly and to a predetermined extent in a direction to I cause progressive grinding of the work, and for receding the governing-wheelwhen the grinding of an object is completed, and it is desired to remove it and introduce another to be ground. When the hand-lever 68 is being used for this purpose, the worm 62 is lifted and locked out of mesh with the wormwheel- 61.

Passing centrally through and threaded to fit the thread within the swivel sleeve 59 is a screw-threaded stem 69, -the screw-stem being journaled near its outer end in a bracket or supporting arm 70 carried by the main frame of the machine, radially slitted from the bearing in which the shaft is journaled .to its top, and provided with a bolt or screw 71 passing through the two arms made by the slitting of bracket 70. The bolt 71 serves to draw the arms of the bracket 70 together, and thusto clamp or hold the stem 69 against rotation when it is desired to advance or recede the carrier 5 and consequently the governing wheel, by rotation of the sleeve 59. A spoked wheel or hand-wheel 7 2 upon the outer end of screw stem 69 serves as a means of rotating said screw when the pinch or binding screw 71 is backed off to free it.

When this is done, 'or when the screw 69 is to be rotated for advancing and receding the carrier 5, either independently, or together with the slide 6 to which it may be at any time looked, sleeve 59 is locked against turning by dropping the worm 62 into mesh with the worm-wheel 61. At such times the worm or screw 62 will not be turned or manipulated, but will serve, as stated, to hold the worm-wheel 61 and the sleeve 59 against rotation by the hand-lever 68, or through the friction of screw 69 turning therein.

These provisions are made'to enable the carrier 5 to be advanced or receded by the screw 69 when it is desired to traverse the carrier relatively long distances, as in ini-' tially setting the work-rest, and later the governing wheel, relat ively to the grinding wheel. After such adjustments are effected the screw 69 is or may be clamped against rotation, and the slide 6 clamped or locked against longitudinal movement, whereupon the carrier may be moved considerable distances by rotation of the worm 62. When all adjustments are made for progressive grinding without automatic axial feed, the hand-lever 68 will be employed to rotate sleeve 59, the worm 62 being first lifted and locked out of mesh with the worm-wheel 61,

the swing of the lever 68 in each direction being limited and determined by any suitable stops placed in its path. To permit traverse of the carrier 5 through the action of worm 62, a distance materially greater than that effected by backward and forward movement of lever 68, said lever may be disconnected from sleeve 59 or its worm-wheel 61 during the rotation of worm 62, so that such traverse through use of worm 62 shall not be restricted by engagement of lever 68 with either of its limiting stops. After adjustment through rotation of worm-wheel 61 is completed, the lever 68 will be again made fast to the wormwheel or to sleeve 59, so that the sleeve may be again oscillated by said lever. In this way provision is made for all the different manipulations and adjustments incident to the varied classes and modes of grinding above set forth.

of the invention. Thus the sleeve 16 may be made polygonal to prevent rotation in the post; other means than the split Post 13 and split stem 22 and their respective clamping or contracting screws 15 and 51, may be provided; and generally, such changes as fall within the field of the mechanic or engineer as distinguished from those involving invention, are contemplated.

The mechanism illustrated in Figs. 5 and 6 of this application is not specificall claimed herein, but is reserved for, .and c aimed in application Serial No. 128,468, filed on the 14th day of February, 1930, pursuantto official requirement.

We claim p 1. A device for surface of the governing wheel of a centerless grinder, comprising a base adapted to be swiveled on an axis perpendicular to the axis of rotation of said wheel; a post guided and movable laterally upon said base on a line which when the base is in parallel reladressing the peripheral tion to the axis of the wheel to be dressed, is

parallel with said Wheel axis; a sleeve carried and adjustable in said post toward and from the wheel axis but held against rotation in said post; means for clamping said sleeve against movement; a stem axially adjustable within said sleeve" means for so adjusting said stem and holding it where adjusted; a slide carried by said stem and adjustable transversely thereof; and a diamond or dress-' ing tool carried by said slide in position to contact with and dress the periphery of the wheel when said stem is advanced toward the same to the proper extent.

2. A truing and dressing device for the governing wheel of a centerless grinder of the character described, said device comprising a base-plate mounted upon the machine and normally in parallel relation to the axis of the governing wheel but capable of being swung about a pivot axis to place it in angular relation to the axial plane of said governing wheel; a post movable over said baseplate and guided by ways normally parallel with the axis of the governing wheel; a stem carried by said post and axially adjustable toward and from the axis of the governing wheel a slide carried by and movable transversely to said stem; and a diamond carried by said slide; thetraversing of the post'and parts carried thereby serving to carry the diamond transversely across the peripheral face of the governing wheel, the swiveling or swinging of the base-plate serving to de-.

flect the travel of the post and attendant parts from its normal path to accord with the tilting of the axis of the governing wheel, and the adjustment of the diamond in a path transverse to the axis of the diamond-carrying stem servin to compensate for variable elevation of helght or level of the axis. of work ground, relatively to the normal common plane of the wheel axes.

3. A; device for dressing the peripheral surface of the governing-whee]. of a centerless grinder, said device comprising a baseupon and movable in a right line over said base-plate; a tool-supporting stem carried by said post and capable of adjustment toward and from the axis of the govermng- Wheel; a slide carried by and transversely adjustable relatively to said stem; and a diamond or dressing tool carried by said slide,

the tilting support of the governing-wheel andthe swiveling base-plate being provided with like graduations readable in connection with a fixed mark or pointer; whereby the angular adjustment of the base-plate may be made to correspond exactly with the angular tipping of the governing-Wheel axis.

4. The combination with a grinding maplate adapted to be mounted upon the tiltablechine of the centerless type including a bed or support, a grinding wheel rotatably mounted thereon, and a regulating wheel support disposed in opposition to the grinding wheel, of a regulating wheel housing mounted on said support for angular adjustment with respect to the opposed grinding wheel, and a truing tool mechanism carried by said housing including a guide extending transversely of the housing, said guide being supported for angular adjustment as an entirety with the housing and for additional angular adjustment to place same in skewed relation to the housing, a slide mounted for movement along the guide in a path determined by the adjustments thereof, and a truing device carried by the slide and projecting within the housing; whereby said truin device will peripherally traverse a contained regulating Wheel in a plane forming an acute dihedral angle with any intersecting radial plane of the wheel.

5. The combination with a grinding ma chine of the centerless type including a bed or support, a grinding wheel rotatably mounted thereon, and a regulating wheel support disposed in opposition to the grinding wheel, of a regulating wheel housing mounted on said support for angular adjustment with respect to the opposed grinding wheel, and a truing tool mechanism carried by said housing including a guide extending transversely of the housing, said guide being supported for angular adjustment as an entirety with the housing and for additional angular adjustment about an axis lying in a plane intersecting the plane of the axis of the adjustment of the device as an entirety with respect to the housing, a slide mounted for movement along the guide in a path determined by the adjustments thereof, and a truing device carried by the slide and projecting within the housing, said truing device having an operative portion within the housing adjustable in a direction transverse to the direction of movement as determined by the guide, substantially as and for the purpose set forth.

In testimony whereof we have signed our names to this specification.

SOL EINSTEIN. LESTER F. NENNINGER. 

